Contact sensor adapted to be engaged by traveling articles of electrically conducting material

ABSTRACT

A contact sensor adapted to be engaged by traveling articles of electrically conducting material includes a tube of such material set in a grounded metal post and projecting therefrom so as to ensure such engagement. A sleeve of electrically insulating material secured in the tube extends outwardly beyond the end thereof opposite that which the articles approach. A springextended plunger anchored to sleeve has a head extending into the path of the articles for engagement thereby. A through bolt secures the plunger to the sleeve and slides in a cap of insulating material secured over the end of the sleeve. The head is grounded on engagement by an approaching article and a circuit through the bolt is completed to energize a control relay or contactor.

United States Patent [72] Inventor Charles J. Neuhoff Upper YoderTownship, Cambria County, Pa. 211 Appl. No. 813,266 [22] Filed Apr. 3,I969 [45] Patented Apr. 6, 1971 [73] Assignee United States SteelCorporation [54] CONTACT SENSOR ADAPTED TO BE ENGAGED BY TRAVELINGARTICLES OF ELECTRICALLY CONDUCTING MATERIAL 3 Claims, 4 Ih'awing Figs.[52] U.S.Cl 200/6141 [51] Int. Cl HOIh 3/16 [50] Fieldof Search t.ZOO/61.41; 200/46, 166 (B5) [56] References Cited UNITED STATES PATENTS3,005,078 10/1961 Mottu et al. 200/ l 66B5 Primary Examiner-Robert K.Schaefer Assistant ExaminerM. Ginsburg Att0rneyDonald S. Fen'toABSTRACT: A contact sensor adapted to be engaged by traveling articlesof electrically conducting material includes a tube of such material setin a grounded metal post and projecting therefrom so as to ensure suchengagement. A sleeve of electrically insulating material secured in thetube extends outwardly beyond the end thereof opposite that which thearticles approach. A spring-extended plunger anchored to sleeve has ahead extending into the path of the articles for engagement thereby. Athrough bolt secures the plunger to the sleeve and slides in a cap ofinsulating material secured over the end of the sleeve. The head isgrounded on engagement by an approaching article and a circuit throughthe bolt is completed to energize a control relay or contactor.

PATENT ED APR 61% MOTOR POWER SUPPLY IN VEN TOR. CHARLES .1. NEUHOFF Afarney CONTACT SENSOR ADAP'I'EI) TO BE ENGAGED BY TRAVELING ARTICLES OFELECTRICALLY CONDUCTING MATERIAL This invention relates to a contactsensor and, in particular, to a sensor adapted to signal the presence oflarge massive articles traveling on a conveyor.

BACKGROUND OF THE INVENTION It has been the practice heretofore toprovide conveyors for large massive articles with a limit switchengageable thereby, efi'ective to close a control circuit, e.g., to stopthe conveyor on arrival of the articles at a point where removal thereoffrom the conveyor is necessary. An example is the conveyor employed formoving coils of steel strip on end from a hot-rolling mill to acold-rolling mill. The limit switches used, because of their fragileconstruction, were subject to damage by the contact of the coilstherewith, necessitating frequent maintenance work and excessive amountsof down time. The object of my invention is to provide an improvedcontact sensor of simple and sturdy construction, well adapted towithstand heavy impact or shock load and effective instantaneously togive the desired control signal.

The most pertinent prior art known to me is Brickner, US. Pat. No.2,090,l78.

SUMMARY OF THE INVENTION My improved contact sensor comprisesessentially an upstanding grounded post or other support of electricallyconducting material. A tube of such material in electrically conductingrelation with the post extends generally horizontally therefrom in adirection opposite'that in which the articles travel and into the paththereof. A sleeve of electrically insulating material is fitted in thetube and extends beyond the rear end thereof slightly, i.e., the endopposite that adapted to be engaged by the articles. A spring-extendedplunger is anchored in the sleeve and has a head at its forward endsuitable for engagement by the articles. A cap of insulating material isfitted on the rear end of the sleeve and a through bolt of conductingmaterial extends from the head through the cap. Thus, when an article ofelectrically conducting material, grounded on a conveyor, strikes thehead of the plunger, a circuit is completed including a conductorattached to the bolt, a relay or contactor'and a current source havingone terminal grounded. Energization of the relay may serve to stop theconveyor or perforrnsome other desired function.

BRIEF DESCRIPTION OF THE DRAWINGS A complete understanding of theinvention may be obtained from the following detailed description andexplanation which refer to the accompanying drawings illustrating thepresent preferred embodiment. In the drawings:

FIG. I is a partial plan view showing a coil of strip on a conveyor, inarrested position against stop posts fitted with my sensor;

FIG. 2 is an elevation thereof;

FIG. 3 is a section to enlarged scale, taken on the plane of lineIII-III of FIG. 2; and

FIG. 4 is an elementary circuit diagram.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in detailto the drawings, and for the present, particularly to FIGS.- 1 and 2, aconveyor of any suitable construction (that shown being of the rollertype) serves to move coils 11 along a predetermined path. Stop posts 12upstanding from the conveyor arrest each coil as it reaches the limit ofits travel. The posts are fitted with one or more sensors 13, one ofwhich is shown in detail in FIG. 3. Referring now to the latter, posts12 of steel or other electrical conductor are grounded on the conveyorframe (not shown) and are drilled to receive tubes 14 of conductingmetal, secured in such position and at such an angle as to be in thepath of an article approaching the posts on conveyor 10. I

A sleeve 15 of electrically insulating material fits snugly in tube 14and extends a short distance beyond the end thereof away from articlesapproaching on conveyor 10. A cap 29 of electrically insulating materialis threaded on the projecting end of sleeve 15. A plunger 16 includingforward and rear cylinders 17 and 18 with a compression spring 19therebetween, is slidable in sleeve 15. Cylinder 17 has a diaphragm disc20 fixed therein and a ball-head attachment 21 is fitted in the forwardend of the cylinder. A through bolt 22 secured to the diaphragm extendsthrough the cylinders 17 and 18, spring 19 and cap 29. Nuts 23 threadedon the projecting end of the bolt anchor the plunger in the sleeve. Aspacer tube 24 is seated in cylinder 18 behind spring 19. A set screw 25threaded radially through tube 14 engages sleeve 15 to hold it in place.

It will be evident from the foregoing that plunger 16 and its ball-headattachment 21 are completely insulated from the supporting post 12.Thus, a simple circuit shown in FIG. 4 from bolt 22 through a contactorcoil 26 to a current source 27 will be completed on engagement of theattachment 21 by an article of electrically conducting material on theconveyor, if the other terminal of the source be grounded as shown.Operation of the contactor will open the circuit to the motor 28 drivingthe conveyor.

It is apparent from the foregoing description that my invention providesa contact sensor for electrically conducting articles characterized bysimplicity, sturdiness and quick operation. No movement of the articlebeyond initial contact is needed to complete the contactor-energizingcircuit. The construction of the device is such as practically toeliminate maintenance altogether.

Iclaim:

l. A contact sensor adapted to be actuated by engagement of travelingelectrically conducting articles therewith comprising a tube ofelectrically conducting metal, a grounded post of electricallyconducting metal in conducting relation with and supporting said tube sothat one end of said tube is directed toward and terminating short ofthe outer surface of said post in the path of an approaching article, asleeve of electrically insulating material telescoped into said tubewith one end of said sleeve projecting from the end of said tubeopposite said one end of said tube, a telescoping spring extendedplunger slidably disposed in said sleeve with one end thereof projectingfrom the end of said sleeve opposite said projecting end of said sleeveso as to be engageable by and forced into said sleeve when engaged by anapproaching article, a cap of insulating material secured on saidprojecting end of said sleeve, a portion of said plunger extendingsubstantially from one end to the other end of said sleeve andprojecting slidably through said cap, and stop means on said portion ofsaid plunger adapted to engage said cap to limit the extension of saidplunger toward an approaching article.

2. Apparatus as defined by claim 1 characterized by said plungerincluding a through bolt extending slidably through said sleeve and saidcap, and article-engaging means fixed on the end of said bolt oppositethe end thereof projecting through said cap.

3. Apparatus as defined by claim 2 in which said article-engaging meansincludes a cylinder integral with and surrounding the end of said boltopposite from said cap, said cylinder being slidable in said sleeve, andthe ball head disposed in said cylinder with a portion thereof normallyprojecting from the end of said sleeve remote from said cap.

1. A contact sensor adapted to be actuated by engagement of travelingelectrically conducting articles therewith comprising a tube ofelectrically conducting metal, a grounded post of electricallyconducting metal in conducting relation with and supporting said tube sothat one end of said tube is directed toward and terminating short ofthe outer surface of said post in the path of an approaching article, asleeve of electrically insulating material telescoped into said tubewith one end of said sleeve projecting from the end of said tubeopposite said one end of said tube, a telescoping spring-extendedplunger slidably disposed in said sleeve with one end thereof projectingfrom the end of said sleeve opposite said projecting end of said sleeveso as to be engageable by and forced into said sleeve when engaged by anapproaching article, a cap of insulating material secured on saidprojecting end of said sleeve, a portion of said plunger extendingsubstantially from one end to the other end of said sleeve andprojecting slidably through said cap, and stop means on said portion ofsaid plunger adapted to engage said cap to limit the extension of saidplunger toward an approaching article.
 2. Apparatus as defined by claim1 characterized by said plunger including a through bolt extendingslidably tHrough said sleeve and said cap, and article-engaging meansfixed on the end of said bolt opposite the end thereof projectingthrough said cap.
 3. Apparatus as defined by claim 2 in which saidarticle-engaging means includes a cylinder integral with and surroundingthe end of said bolt opposite from said cap, said cylinder beingslidable in said sleeve, and the ball head disposed in said cylinderwith a portion thereof normally projecting from the end of said sleeveremote from said cap.